Glossary: El Niņo
El Niņo
El Niņo translates from the Spanish as "the little boy" or "the Christ child," and is so called because the weak warm ocean current occurs along the western coast of South America around Christmas. El Niņo is a very good example of the complex, intimate exchange between winds in the atmosphere and ocean currents.
In most years, strong, prevailing trade winds blow westward dragging the Earth's warmest surface waters across the Pacific to Australia and Indonesia. But every few years the trade winds slacken or change direction. Within a few weeks, the ocean responds to these changes. Without winds to hold it back, the warm waters to the west slosh back towards the coast of South America. This begins an El Niņo. Some years the water warms up as much as 5°C or more.
The atmosphere then responds to the rise in ocean temperature. The moist air above the warm waters also warms. It becomes buoyant enough to form clouds and tropical storms. The atmospheric stirrings cause heavy thunderstorms over the central Pacific, which in turn drive the jet streams that guide weather systems across the earth.
At one time, El Niņo was thought to affect only South America's Pacific Coast, bringing flooding rains to Peru and ruining the anchovy fishery. Now we know El Niņo can do very strange things to the world's weather for a year or even longer.
In some areas, El Niņo means fairly predictable weather. For instance, it is almost sure to cause droughts in northeastern Brazil, eastern Australia and southern Africa, produce floods and mudslides in Ecuador, quiet the hurricane season in the Atlantic Ocean, delay the Indian monsoon, and bring copious winter rains to southern California.
In Canada, El Niņo's impacts are considered marginal, showing up most clearly during wintertime in western Canada. But, El Niņo is both good and bad news for Canadians. For example, in British Columbia schools of hungry mackerel riding the El Niņo wave may devour young sockeye stock. For skiers, El Niņo's usually snow-free winter is not welcome news. On the other hand, an El Niņo year also correlates with a wetter spring and a warmer summer, making for good crop weather. When El Niņo occurs, it seems to have something for everyone.
- RSS & Data
